EP3781835B1 - Fluid damper with inertial fluid damping for a vehicle suspension - Google Patents

Fluid damper with inertial fluid damping for a vehicle suspension Download PDF

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Publication number
EP3781835B1
EP3781835B1 EP19720967.9A EP19720967A EP3781835B1 EP 3781835 B1 EP3781835 B1 EP 3781835B1 EP 19720967 A EP19720967 A EP 19720967A EP 3781835 B1 EP3781835 B1 EP 3781835B1
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EP
European Patent Office
Prior art keywords
piston
chamber
shock absorber
wall
hydraulic fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP19720967.9A
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German (de)
French (fr)
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EP3781835A1 (en
Inventor
Jean CHILLON
Christophe Monteil
Francis Bontron
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stellantis Auto SAS
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Stellantis Auto SAS
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Publication date
Priority claimed from FR1853332A external-priority patent/FR3080162B1/en
Priority claimed from FR1903247A external-priority patent/FR3094435B1/en
Application filed by Stellantis Auto SAS filed Critical Stellantis Auto SAS
Publication of EP3781835A1 publication Critical patent/EP3781835A1/en
Application granted granted Critical
Publication of EP3781835B1 publication Critical patent/EP3781835B1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
    • F16F9/14—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
    • F16F9/16—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
    • F16F9/22—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with one or more cylinders each having a single working space closed by a piston or plunger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F7/00—Vibration-dampers; Shock-absorbers
    • F16F7/10—Vibration-dampers; Shock-absorbers using inertia effect
    • F16F7/1034—Vibration-dampers; Shock-absorbers using inertia effect of movement of a liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
    • F16F9/14—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
    • F16F9/16—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
    • F16F9/18—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein
    • F16F9/182—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein comprising a hollow piston rod
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/34—Special valve constructions; Shape or construction of throttling passages
    • F16F9/346—Throttling passages in the form of slots arranged in cylinder walls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/50—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
    • F16F9/504—Inertia, i.e. acceleration,-sensitive means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
    • F16F9/14—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
    • F16F9/16—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
    • F16F9/18—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein
    • F16F9/20—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein with the piston-rod extending through both ends of the cylinder, e.g. constant-volume dampers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/50—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
    • F16F9/512—Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity
    • F16F9/5126—Piston, or piston-like valve elements

Definitions

  • the invention relates to the field of shock absorption, more particularly in the area of automobile vehicle suspensions.
  • the shock absorber illustrated in Figures 14 and 15 of this document comprises, essentially, a first element forming a cylindrical envelope and a second element comprising a rod supporting a first and a second piston, said pistons sliding axially in the cylindrical envelope .
  • the latter is separated axially into two hydraulic chambers, the first of said chambers forming with the first piston a first so-called inertial hydraulic circuit.
  • the latter further comprises a conduit forming a winding around the first generally cylindrical element, so that the movement of the first piston relative to the first chamber displaces a hydraulic fluid in the chamber through the conduit, this movement forming inertial damping.
  • the second of the chambers forms, with the second piston, a second hydraulic circuit called damping in that the piston includes a leakage passage of reduced section for a hydraulic fluid.
  • This damper is interesting in that it combines two types of damping, namely classic damping whose force is a function of the speed of the relative sliding movement between the rod and the cylinder and inertial damping whose force is a function of the acceleration of said movement.
  • it has a significant axial bulk.
  • the production, shaping and installation of the spiral conduit presents difficulties, particularly in terms of achieving sealing with the body of the cylindrical envelope. Corrosion resistance of spiral conduit can also present challenges.
  • the inertial damping function is permanently active, which, under certain operating conditions, can be negative.
  • the inertial damping function cannot be easily calibrated differently without profoundly modifying the shape of the ducts, which poses a problem in the case of several applications on different vehicles of different masses.
  • the invention aims to overcome at least one of the disadvantages of the aforementioned state of the art. More particularly, the invention aims to propose a shock absorber for a motor vehicle suspension, which overcomes at least one of the disadvantages of the aforementioned state of the art. More particularly, the invention aims to propose a shock absorber which is compact, economical, easily configurable and efficient.
  • the subject of the invention is a shock absorber for a motor vehicle suspension, comprising a first element intended to be fixed to one of a movable part of the suspension and a fixed part of the vehicle and a second element, positioned concentrically around of the first element, capable of sliding axially relative to the first element and intended to be fixed to the other of the movable part of the suspension and the fixed part of the vehicle.
  • the first element and the second element form a damping hydraulic circuit and an inertial hydraulic circuit.
  • the first element is a cylinder forming a cylindrical chamber and the second element comprises an internal piston slidably mounted in the cylindrical chamber and a rod linked to said internal piston.
  • the cylindrical chamber and the interior piston correspond to one of the damper and inertial hydraulic circuits.
  • An outer cylinder is linked to the rod and concentrically surrounds the first element so as to slide along the outer wall of the first element and to form an outer chamber with the first element.
  • the first element comprises an external annular portion forming at least one annular piston.
  • the shock absorber includes a cylindrical wall concentrically surrounding a portion of the first element to form an annular chamber.
  • the at least one annular piston sliding along said cylindrical wall in the annular chamber.
  • the cylindrical wall comprises a helical groove forming, opposite the at least one annular piston, at least one passage for the hydraulic fluid during sliding of the at least one annular piston along the cylindrical wall.
  • the helical groove has a variable pitch so as to vary the length of the passage(s) for the hydraulic fluid as a function of the sliding position of the at least one annular piston relative to the wall.
  • the at least one annular piston extends axially over at least two turns of the helical groove.
  • the at least one annular piston comprises at least one axial leakage passage for the hydraulic fluid and at least one closing valve configured to close said passage when the sliding stroke of said at least one piston per relationship to the wall is greater than a predetermined value.
  • the outer chamber also forms said annular chamber in which the at least one annular piston is able to slide.
  • the at least one piston comprises at least two pistons, the closing valves of said pistons having different closing strokes.
  • the at least one piston comprises at least one relief valve capable of opening an axial discharge passage for the hydraulic fluid in the event of overpressure of said fluid.
  • a cylindrical intermediate wall is positioned capable of sliding along the outer wall of the first element, said intermediate wall delimiting the intermediate chamber which forms said annular chamber, which is delimited on one side by said cylindrical wall and on the other side by the exterior wall of the first element.
  • the annular chamber comprising a hydraulic fluid, the annular piston being able to slide along the annular chamber, said annular chamber comprising return means positioned between the annular piston and the intermediate wall.
  • the return means which comprise at least two springs, a first spring which is positioned in support between a first axial face of the piston and a first edge facing the annular chamber and a second spring being positioned in support between a second axial face of the intermediate piston and a second edge facing the annular chamber.
  • the outer chamber comprises a hydraulic fluid and a ring which delimits said outer chamber into two portions, said ring being adapted to control the transfer of hydraulic fluid between the two portions.
  • the ring comprises at least one relief valve allowing an exchange of hydraulic fluid between the two portions of the external chamber beyond a certain fluid pressure in one of said two portions and a leak valve allowing a leak calibrated permanent hydraulic fluid between the two portions of the outer chamber.
  • the invention also relates to a motor vehicle comprising at least one suspension shock absorber, remarkable in that the at least one shock absorber conforms to the invention.
  • the measures of the invention are interesting in that they make it possible to produce a particularly efficient shock absorber while remaining simple and compact in construction.
  • the fact of providing the shock absorber and inertial hydraulic circuits concentrically makes it possible to limit the length of the shock absorber.
  • the fact of providing, for the second sliding element, in addition to the rod and the piston cooperating with the cylinder of the first sliding element, an external cylinder surrounding the first sliding element makes it possible to produce in a particularly compact and fairly simple manner a second chamber, in external occurrence, and thus a second hydraulic circuit.
  • the concentric arrangement makes it possible to obtain a large thrust surface of the circumferential piston, which makes it possible to reduce the inertial mass of the hydraulic fluid.
  • the fact of forming the volume of inertial hydraulic fluid by a groove in the wall along which a piston slides is advantageous in that the inertial passage for the fluid is directly in the hydraulic chamber and is thus protected from attacks. external, such as corrosion.
  • this construction avoids the difficulties of achieving sealing with a conduit as in the state of the art.
  • the pitch of the helical groove can be varied in order to vary the mass of inertial hydraulic fluid as a function of the sliding level of the first element relative to the second.
  • the closing and relief valves make it possible to activate and deactivate, respectively, the inertial function in a controlled manner, which is particularly favorable to increasing the driving comfort of the vehicle on normal roads while ensuring sufficient damping during longer travel. important, such as on roads in poor condition.
  • the creation of an auxiliary chamber for deactivation of the inertial function provides more flexibility of adjustment.
  • THE figures 1 to 3 illustrate a first embodiment of the invention.
  • FIG. 1 is a schematic view, in longitudinal section, of a shock absorber according to a first embodiment of the invention.
  • the longitudinal section passes through the axis of the shock absorber 2.
  • the latter essentially comprises a first element 4 and a second element 6, capable of sliding relative to each other.
  • Each of the first and second sliding elements 4 and 6 is intended to be fixed, as desired, to a moving part of the suspension of a vehicle or to a fixed part of the bodywork of said vehicle, respectively.
  • the first element 4 comprises a cylinder 8 delimiting a first generally cylindrical chamber 10. It also comprises an outer annular portion 12 forming an annular piston.
  • the second element 6 comprises, for its part, a piston 14 supported by a rod 16 and slidably mounted in the cylindrical chamber 10.
  • the chamber 10 comprises a hydraulic fluid, advantageously viscous with a viscosity greater than or equal to that of Citro ⁇ n ® suspension fluid (LDS), namely greater than or equal to 18 mm 2 /s at 40°C and/or 5.9 mm 2 / s at 100°C.
  • LDS Citro ⁇ n ® suspension fluid
  • the piston 14 comprises one or more passages with potentially variable restriction as a function of pressure difference (not shown), connecting the two chamber portions 10, so that relative sliding enters, on the one hand, the piston 14 and the rod 16, and on the other hand the cylinder 8 causes a forced circulation of the hydraulic fluid through the restricted passage(s) on the piston 14.
  • the resistance to the flow through this or these passages generates at the level of the rod 16 and at the level of the cylinder 8 forces which are essentially proportional to the speed of flow of the fluid and therefore to the speed of relative sliding between the piston 14 and the cylinder.
  • This principle of depreciation is well known in itself to those skilled in the art.
  • the second sliding element 6 of the shock absorber 2 comprises, in addition to the piston 14 and the rod 16, an outer cylinder 18 surrounding the cylinder 8 of the first sliding element 4, and, therefore, the rod 16 and the piston 14.
  • the outer cylinder 18 is rigidly linked to the rod 16. More specifically, the outer cylinder 18 is slidably mounted on the outer cylindrical surface of the cylinder 8. It comprises a wall 20 surrounding the cylinder 8 and at a radial distance from said cylinder in order to form, with said surface external cylindrical, a second annular chamber 22. This comprises an annular piston 12 linked to the cylinder 8. This piston also separates the second chamber 22 into two chamber portions 22.1 and 22.2.
  • the wall 20 delimiting the chamber 22 has on its interior surface 20.1 a groove 24 formed helically, in particular by machining in the thickness of the wall 20 from the interior surface 20.1.
  • the annular piston 12 extends axially over at least one turn of the helical groove, preferably over at least two turns of said groove, more preferably still over at least three turns or more.
  • the annular piston 12 comprises at least one axial leakage passage 26 and at least one closing valve 28 held in an axially neutral position by the springs 30. In this neutral position, the closing valve 28 although closing at least for the most part the passage 26 can move axially between the stops and seats 32.
  • the second chamber 22 is filled with a hydraulic fluid, preferably different from that of the first chamber.
  • This fluid is advantageously a heavy fluid of low viscosity, in this case with a viscosity less than or equal to that of glycol.
  • the passage 26 in the annular piston 12, combined with the closing valve 28 held in the central position by the springs 30 and capable of moving axially over a given stroke, allows the inertial hydraulic circuit formed in the second chamber 22 to only be active for suspension travel greater than a given limit.
  • the stroke can be greater than 2mm and/or less than 40mm.
  • FIG 2 is a sectional view II-II of the shock absorber of the figure 1 , at the level of the annular piston 12.
  • the closing valve 28 described above extends circumferentially, in this case over a half-turn. However, it is understood that other configurations, such as 3 ⁇ 4 turn, or even more, are also possible.
  • the annular piston 12 can also comprise one or more discharge valves 34, arranged from a fluidic point of view in parallel to the closing valve 28. These discharge valves 34 are configured to open and therefore allow passage the fluid in the presence of a pressure difference reaching or exceeding a predetermined limit. This allows the inertial hydraulic circuit to limit its effect in the presence of sliding movements with great acceleration.
  • the deactivation of the inertial circuit can be done in both directions, that is to say when the shock absorber is in compression or attack, and when it is in extension or relaxation.
  • at least one relief valve can then be provided in each of the flow directions between the two portions 22.1 and 22.2 of the chamber 22.
  • discharge valve(s) 34 can be arranged on the closing valve 28.
  • the latter can be formed of several elements distributed over the circumference of the piston 12.
  • winding pitch of the helical groove can be variable so as to vary the inertial mass depending on the degree of depression of the shock absorber.
  • FIG. 3 illustrates a variant of the shock absorber of the figure 1 , where two annular pistons 12.1 and 12.2 are arranged in the chamber 22, at an axial distance from one another. Each includes a passage 26.1 and 26.2 for the hydraulic fluid, and also a closing valve 28.1 and 28.2 held by springs 30.1 and 30.2, respectively. It can be observed that for the first piston 12.1, the stroke of the closing valve 28.1 is less than that of the closing valve 28.2 of the second piston 12.2. It can also be observed that the number of turns made by the groove 24 opposite the first piston 12.1 is different, in this case lower, than the number of turns made by the groove 24 opposite the second piston 12.2. Such a configuration is interesting in that it allows the use of two different inertia masses advantageously with different activation thresholds. Also discharge valves of different characteristics can be provided on these pistons 12.1 and 12.2, which makes it possible to obtain different saturation thresholds.
  • the shock absorber which has just been described is particularly interesting in that it combines a hydraulic circuit with conventional damping and an inertial hydraulic circuit, and this in a compact, economical and efficient manner.
  • the inertial hydraulic circuit makes it possible to participate in damping for greater travel, which makes it possible to provide a lower level of classic damping, thus providing greater comfort on normal roads.
  • FIGS. 4 and 5 are schematic views, in longitudinal section, of a shock absorber 102 according to a second embodiment of the invention.
  • axial wall is understood to mean a wall oriented along a vertical axis of the shock absorber 102 following the orientation of the Figure 4 and by the term radial wall a wall oriented along a horizontal axis of the shock absorber 102 always following the orientation of the Figure 4 .
  • the longitudinal section passes through the axis of symmetry of the shock absorber 102.
  • the shock absorber 102 comprises a first element 104 and a second element 106, capable of sliding relative to each other.
  • Each of the first and second elements 104 and 106 is intended to be fixed, as desired, to a moving part of the suspension of a vehicle or to a fixed part of the bodywork of said vehicle, respectively.
  • the first element 104 comprises an interior cylinder 108 delimiting a generally cylindrical interior chamber 110.
  • the second element 106 comprises an interior piston 114 supported by a rod 116 and slidably mounted in the interior chamber 110.
  • the interior cylinder 108 is closed at each of its two axial ends, the upper closure being crossed by the rod 116 (following the orientation of the Figure 4 ) and comprises sealing means (not shown) with the rod 116, these sealing means being in themselves well known to those skilled in the art.
  • the inner chamber 110 comprises a hydraulic fluid, advantageously viscous with a viscosity greater than or equal to that of Citro ⁇ n ® suspension fluid (LDS), namely greater than or equal to 18 mm 2 /s at 40°C and/or 5.9 mm 2 /s at 100°C.
  • LDS Citro ⁇ n ® suspension fluid
  • the interior piston 114 comprises one or more passages with potentially variable restriction as a function of pressure difference (not shown), connecting the two portions of the interior chamber 110, so that relative sliding enters, on the one hand, the inner piston 114 and the rod 116, and on the other hand the inner cylinder 108 causes a forced circulation of the hydraulic fluid through the restricted passage(s) on the inner piston 114.
  • the second element 106 of the shock absorber 102 comprises, in addition to the inner piston 114 and the rod 116, an outer cylinder 118 surrounding the inner cylinder 108 of the first element 104, and, therefore, the rod 116 and the inner piston 114.
  • the outer cylinder 118 is rigidly linked to the rod 116. More specifically, the outer cylinder 118 is slidably mounted on the outer cylindrical surface of the inner cylinder 108.
  • the outer cylinder 118 has a cavity that is formed along its inner cylindrical surface.
  • the outer cylinder 118 is positioned in a sliding and sealed manner, at both ends of said cavity, around the inner cylinder 108.
  • an intermediate element 120 of cylindrical shape In said cavity of the outer cylinder 118 is positioned an intermediate element 120 of cylindrical shape.
  • an exterior chamber 125 is delimited.
  • the intermediate member 120 has a cavity which is formed along its inner cylindrical surface.
  • the intermediate element 120 is positioned in a sliding and sealed manner, at these two ends, around the inner cylinder 108.
  • annular chamber Between the interior cylindrical surface of the cavity of the intermediate element 120 and the exterior cylindrical surface of the exterior cylinder 118 is delimited an intermediate chamber 122 called an annular chamber.
  • the inner cylinder 108 comprises a collar, projecting from its outer cylindrical surface, which forms an intermediate piston 112, of annular shape, capable of sliding along the annular chamber 122 as a function of the relative movement between the inner cylinder 108 and the intermediate element 120.
  • the intermediate piston 112 separates the annular chamber 122 into two portions 122.1 and 122.2. Depending on the orientation of the shock absorber 102 as shown in Figure 4 , is formed an upper portion 122.1 of the annular chamber 122 and a lower portion 122.2 of the annular chamber 122.
  • a spring 127 bearing between each of the two axial edges of the annular chamber 122 and the corresponding face of the annular piston 112, so that, always following the orientation of the shock absorber as as shown in Figure 104, a first top spring 127.1 is positioned in the upper portion 122.1 of the annular chamber 122 and a second bottom spring 127.2 is positioned in the lower portion 122.2 of the annular chamber 122.
  • the intermediate element 120 has along its radial interior surface a groove 124 formed in a helical manner, in particular by machining in the thickness of the intermediate wall 120 from its radial interior surface.
  • the annular piston 112 extends axially over at least one turn of the helical groove 124, preferably over at least two turns of said helical groove 124, more preferably still over at least three turns or more.
  • winding pitch of the helical groove can be variable along the radial interior surface of the intermediate element 120, so as to vary the inertial mass as a function of the degree of depression of the shock absorber. 112.
  • the intermediate piston 112 comprises at least one axial leakage passage 126 and at least one closing valve 128 held in an axially neutral position by springs 130 positioned on either side of said closing valve 128.
  • Stops 132 positioned at both ends of the axial leakage passage 126 form bearing surfaces for the springs 130 of the intermediate piston 112.
  • the closing valve 128, although blocking at least the majority of the passage 126, can move axially between the stops 132.
  • the annular chamber 122 is filled with a hydraulic fluid, preferably different from that of the interior chamber 110.
  • This fluid is advantageously a heavy fluid of low viscosity, in this case with a viscosity less than or equal to that of glycol.
  • a ring 123 delimits the outer chamber 125 into two portions 125.1 and 125.2.
  • the outer chamber 125 is separated from the annular chamber 122 and the inner chamber 110, making it possible to provide a hydraulic fluid potentially different from that in particular of the annular chamber 122.
  • first discharge valve 133 which allows an exchange of fluid from the first portion 125.1 of the outer chamber 125 towards the second portion 125.2 of the outer chamber 125.
  • a second discharge valve 134 which allows an exchange of fluid from the second portion 125.2 of the outer chamber 125 towards the first portion 125.1 of the outer chamber 125.
  • a leak valve 135 allowing a permanent calibrated leak of the hydraulic fluid between the two portions 125.1 and 125.2 of the outer chamber 125.
  • the volumes of portions 122.1 and 122.2 of the chamber 122 will vary in opposite directions and, therefore, cause the fluid to pass through and along the portion of the groove 124 which is located opposite the annular piston 112.
  • the intermediate wall 120 is held axially in the central position by the springs 127.
  • the intermediate piston 112 advantageously does not include relief valves, these being provided on the ring 123 which delimits the outer chamber 125 into two portions 125.1 and 125.2.
  • the operation of the shock absorber is therefore as follows.
  • the closing valve 128 fails to abut on the seats 132, which has the effect that the inertial hydraulic circuit does not generate significant force and is therefore inactive.
  • This resistant force which tends to move the wall 120 is taken up by an increase in pressure in the portion of the outer chamber 125 whose volume tends to decrease by the movement of the wall 120. This pressure is transmitted to the discharge valves 133 and 134 and the leak valve 135 on the ring 123.
  • a fluid other than the inertial fluid can be used to cooperate with the discharge valves 133 and 134.
  • This provides more fine adjustment of the behavior of the inertial circuit, in particular at the level of its deactivation threshold.
  • the operating speeds are independent and better controllable.
  • the deactivation of the inertial circuit can be done in both directions, that is to say when the shock absorber is in compression or attack, and when it is in extension or relaxation.
  • a single relief valve capable of working in both directions can be provided.
  • the calibrated leakage valve intervenes only slightly during the operation of the shock absorber and during the operation of the inertial circuit, but allows the assembly to reposition itself in the neutral position after having been requested for a next use knowing that both discharge valves are then in the closed position.

Description

L'invention a trait au domaine de l'amortissement de chocs, plus particulièrement au niveau des suspensions de véhicules automobiles.The invention relates to the field of shock absorption, more particularly in the area of automobile vehicle suspensions.

Le document de brevet publié US 2013/0037362 A1 divulgue différentes configurations d'amortisseur de chocs notamment pour suspension de véhicule automobile. Plus particulièrement, l'amortisseur illustré aux figures 14 et 15 de ce document comprend, essentiellement, un premier élément formant une enveloppe cylindrique et un deuxième élément comprenant une tige supportant un premier et un deuxième piston, lesdits pistons coulissant axialement dans l'enveloppe cylindrique. Cette dernière est séparée axialement en deux chambres hydrauliques, la première desdites chambres formant avec le premier piston un premier circuit hydraulique dit inertiel. Ce dernier comprend, en outre, une conduite formant un enroulement autour du premier élément généralement cylindrique, de sorte à ce que le déplacement du premier piston par rapport à la première chambre déplace un fluide hydraulique dans la chambre au travers du conduit, ce déplacement formant un amortissement inertiel. La deuxième des chambres forme, avec le deuxième piston, un deuxième circuit hydraulique dit d'amortissement en ce que le piston comprend un passage de fuite de section réduite pour un fluide hydraulique. Cet amortisseur est intéressant en ce qu'il combine deux types d'amortissement, à savoir un amortissement classique dont la force est fonction de la vitesse du mouvement de coulissement relatif entre la tige et le cylindre et un amortissement inertiel dont la force est fonction de l'accélération dudit mouvement. Il présente cependant un encombrement axial important. De plus, la réalisation, la mise en forme et la mise en place du conduit spiralé présente des difficultés notamment au niveau de la réalisation de l'étanchéité avec le corps de l'enveloppe cylindrique. La résistance à la corrosion du conduit spiralé peut également présenter des difficultés. Aussi, avec cet amortisseur, la fonction d'amortissement inertiel est en permanence active, ce qui, dans certaines conditions de fonctionnement, peut s'avérer négatif. De plus, avec cet amortisseur, la fonction d'amortissement inertiel ne peut être facilement calibrée différemment sans modifier profondément la forme des conduits, ce qui pose un problème dans le cas de plusieurs applications sur différents véhicules de masses différentes.The published patent document US 2013/0037362 A1 discloses different configurations of shock absorbers in particular for motor vehicle suspension. More particularly, the shock absorber illustrated in Figures 14 and 15 of this document comprises, essentially, a first element forming a cylindrical envelope and a second element comprising a rod supporting a first and a second piston, said pistons sliding axially in the cylindrical envelope . The latter is separated axially into two hydraulic chambers, the first of said chambers forming with the first piston a first so-called inertial hydraulic circuit. The latter further comprises a conduit forming a winding around the first generally cylindrical element, so that the movement of the first piston relative to the first chamber displaces a hydraulic fluid in the chamber through the conduit, this movement forming inertial damping. The second of the chambers forms, with the second piston, a second hydraulic circuit called damping in that the piston includes a leakage passage of reduced section for a hydraulic fluid. This damper is interesting in that it combines two types of damping, namely classic damping whose force is a function of the speed of the relative sliding movement between the rod and the cylinder and inertial damping whose force is a function of the acceleration of said movement. However, it has a significant axial bulk. In addition, the production, shaping and installation of the spiral conduit presents difficulties, particularly in terms of achieving sealing with the body of the cylindrical envelope. Corrosion resistance of spiral conduit can also present challenges. Also, with this shock absorber, the inertial damping function is permanently active, which, under certain operating conditions, can be negative. Furthermore, with this damper, the inertial damping function cannot be easily calibrated differently without profoundly modifying the shape of the ducts, which poses a problem in the case of several applications on different vehicles of different masses.

On connait encore le document US3237931A correspondant au préambule de la revendication 1.We still know the document US3237931A corresponding to the preamble of claim 1.

L'invention a pour objectif de pallier au moins un des inconvénients de l'état de la technique susmentionné. Plus particulièrement, l'invention a pour objectif de proposer un amortisseur de chocs pour suspension de véhicule automobile, qui pallie au moins un des inconvénients de l'état de la technique susmentionné. Plus particulièrement, l'invention a pour objectif de proposer un amortisseur qui soit compact, économique, facilement paramétrable et performant.The invention aims to overcome at least one of the disadvantages of the aforementioned state of the art. More particularly, the invention aims to propose a shock absorber for a motor vehicle suspension, which overcomes at least one of the disadvantages of the aforementioned state of the art. More particularly, the invention aims to propose a shock absorber which is compact, economical, easily configurable and efficient.

L'invention a pour objet un amortisseur pour suspension de véhicule automobile, comprenant un premier élément destiné à être fixé à l'une d'une partie mobile de la suspension et d'une partie fixe du véhicule et un deuxième élément, positionné concentriquement autour du premier élément, apte à coulisser axialement par rapport au premier élément et destiné à être fixé à l'autre de la partie mobile de la suspension et de la partie fixe du véhicule. Le premier élément et le deuxième élément forment un circuit hydraulique amortisseur et un circuit hydraulique inertiel. Le premier élément est un cylindre formant une chambre cylindrique et le deuxième élément comprend un piston intérieur monté coulissant dans la chambre cylindrique et une tige liée audit piston intérieur. La chambre cylindrique et le piston intérieur correspondent à un des circuits hydrauliques amortisseur et inertiel. Un cylindre extérieur est lié à la tige et entoure concentriquement le premier élément de manière à coulisser le long de la paroi extérieure du premier élément et à former avec le premier élément une chambre extérieure. Selon l'invention, le premier élément comprend une portion annulaire extérieure formant au moins un piston annulaire. L'amortisseur comprend une paroi cylindrique entourant concentriquement une partie du premier élément pour former une chambre annulaire. Le au moins un piston annulaire coulissant le long de ladite paroi cylindrique dans la chambre annulaire. La paroi cylindrique comprend une rainure hélicoïdale formant, en vis-à-vis du au moins un piston annulaire, au moins un passage pour le fluide hydraulique lors d'un coulissement du au moins un piston annulaire le long de la paroi cylindrique.The subject of the invention is a shock absorber for a motor vehicle suspension, comprising a first element intended to be fixed to one of a movable part of the suspension and a fixed part of the vehicle and a second element, positioned concentrically around of the first element, capable of sliding axially relative to the first element and intended to be fixed to the other of the movable part of the suspension and the fixed part of the vehicle. The first element and the second element form a damping hydraulic circuit and an inertial hydraulic circuit. The first element is a cylinder forming a cylindrical chamber and the second element comprises an internal piston slidably mounted in the cylindrical chamber and a rod linked to said internal piston. The cylindrical chamber and the interior piston correspond to one of the damper and inertial hydraulic circuits. An outer cylinder is linked to the rod and concentrically surrounds the first element so as to slide along the outer wall of the first element and to form an outer chamber with the first element. According to the invention, the first element comprises an external annular portion forming at least one annular piston. The shock absorber includes a cylindrical wall concentrically surrounding a portion of the first element to form an annular chamber. The at least one annular piston sliding along said cylindrical wall in the annular chamber. The cylindrical wall comprises a helical groove forming, opposite the at least one annular piston, at least one passage for the hydraulic fluid during sliding of the at least one annular piston along the cylindrical wall.

Selon une variante, la rainure hélicoïdale présente un pas variable de manière à faire varier la longueur du ou des passages pour le fluide hydraulique en fonction de la position de coulissement du au moins un piston annulaire par rapport à la paroi.According to a variant, the helical groove has a variable pitch so as to vary the length of the passage(s) for the hydraulic fluid as a function of the sliding position of the at least one annular piston relative to the wall.

De manière avantageuse, l'au moins un piston annulaire s'étend axialement sur au moins deux tours de la rainure hélicoïdale.Advantageously, the at least one annular piston extends axially over at least two turns of the helical groove.

Selon une caractéristique de l'invention, l'au moins un piston annulaire comprend au moins un passage axial de fuite pour le fluide hydraulique et au moins un clapet de fermeture configuré pour fermer ledit passage lorsque la course de coulissement dudit au moins un piston par rapport à la paroi est supérieur à une valeur prédéterminée.According to one characteristic of the invention, the at least one annular piston comprises at least one axial leakage passage for the hydraulic fluid and at least one closing valve configured to close said passage when the sliding stroke of said at least one piston per relationship to the wall is greater than a predetermined value.

Selon un premier mode de réalisation de l'invention, la chambre extérieure forme aussi ladite chambre annulaire dans laquelle est apte à coulisser le au moins un piston annulaire. Le au moins un piston comprend au moins deux pistons, les clapets de fermeture desdits pistons présentant des courses de fermeture différentes. L'au moins un piston comprend au moins un clapet de décharge apte à ouvrir un passage axial de décharge pour le fluide hydraulique en cas de surpression dudit fluide.According to a first embodiment of the invention, the outer chamber also forms said annular chamber in which the at least one annular piston is able to slide. The at least one piston comprises at least two pistons, the closing valves of said pistons having different closing strokes. The at least one piston comprises at least one relief valve capable of opening an axial discharge passage for the hydraulic fluid in the event of overpressure of said fluid.

Préférentiellement, selon un second mode de réalisation de l'invention, entre le premier élément et le deuxième élément, est positionnée une paroi intermédiaire cylindrique apte à coulisser le long la paroi extérieure du premier élément, ladite paroi intermédiaire délimitant la chambre intermédiaire qui forme ladite chambre annulaire, qui est délimitée d'un côté par ladite paroi cylindrique et de l'autre côté par la paroi extérieure du premier élément. La chambre annulaire comportant un fluide hydraulique, le piston annulaire étant apte à coulisser le long de la chambre annulaire, ladite chambre annulaire comportant des moyens de rappel positionnés entre le piston annulaire et la paroi intermédiaire.Preferably, according to a second embodiment of the invention, between the first element and the second element, a cylindrical intermediate wall is positioned capable of sliding along the outer wall of the first element, said intermediate wall delimiting the intermediate chamber which forms said annular chamber, which is delimited on one side by said cylindrical wall and on the other side by the exterior wall of the first element. The annular chamber comprising a hydraulic fluid, the annular piston being able to slide along the annular chamber, said annular chamber comprising return means positioned between the annular piston and the intermediate wall.

Selon une réalisation, les moyens de rappel qui comportent au moins deux ressort, un premier ressort qui est positionné en appui entre une première face axiale du piston et un premier bord en regard de la chambre annulaire et un second ressort étant positionné en appui entre une seconde face axiale du piston intermédiaire et un second bord en regard de la chambre annulaire.According to one embodiment, the return means which comprise at least two springs, a first spring which is positioned in support between a first axial face of the piston and a first edge facing the annular chamber and a second spring being positioned in support between a second axial face of the intermediate piston and a second edge facing the annular chamber.

Selon une réalisation, la chambre extérieure comporte un fluide hydraulique et une bague qui délimite en deux portions ladite chambre extérieure, ladite bague étant adaptée pour contrôler le transfert de fluide hydraulique entre les deux portions.According to one embodiment, the outer chamber comprises a hydraulic fluid and a ring which delimits said outer chamber into two portions, said ring being adapted to control the transfer of hydraulic fluid between the two portions.

Selon une réalisation, la bague comporte au moins un clapet de décharge permettant un échange du fluide hydraulique entre les deux portions de la chambre extérieure au-delà d'une certaine pression de fluide dans une desdites deux portions et un clapet de fuite permettant une fuite permanente calibrée du fluide hydraulique entre les deux portions de la chambre extérieure.According to one embodiment, the ring comprises at least one relief valve allowing an exchange of hydraulic fluid between the two portions of the external chamber beyond a certain fluid pressure in one of said two portions and a leak valve allowing a leak calibrated permanent hydraulic fluid between the two portions of the outer chamber.

L'invention a également pour objet un véhicule automobile comprenant au moins un amortisseur de suspension, remarquable en ce que l'au moins un amortisseur est conforme à l'invention.The invention also relates to a motor vehicle comprising at least one suspension shock absorber, remarkable in that the at least one shock absorber conforms to the invention.

Les mesures de l'invention sont intéressantes en ce qu'elles permettent de réaliser un amortisseur particulièrement performant tout en restant de construction simple et compacte. En effet, le fait de prévoir les circuits hydrauliques amortisseur et inertiel de manière concentrique permet de limiter la longueur de l'amortisseur. Le fait de prévoir, pour le deuxième élément coulissant, outre la tige et le piston coopérant avec le cylindre du premier élément coulissant, un cylindre extérieur entourant le premier élément coulissant permet de réaliser de manière particulièrement compacte et assez simple une deuxième chambre, en l'occurrence extérieure, et ainsi un deuxième circuit hydraulique. Aussi, l'agencement concentrique permet d'obtenir une surface de poussée du piston circonférentiel importante, ce qui permet de réduire la masse inertielle du fluide hydraulique. Par ailleurs, le fait de former le volume de fluide hydraulique inertiel par une rainure dans la paroi le long de laquelle coulisse un piston, est avantageux en ce que le passage inertiel pour le fluide est directement dans la chambre hydraulique et est ainsi protégé des agressions extérieures, comme notamment la corrosion. Aussi, cette construction évite les difficultés de réalisation d'étanchéité avec un conduit comme dans l'état de la technique. Aussi, grâce à cette construction, le pas de la rainure hélicoïdale peut être varié afin de faire varier la masse de fluide hydraulique inertiel en fonction du niveau de coulissement du premier élément par rapport au deuxième. Les clapets de fermeture et de décharge permettent d'activer et désactiver, respectivement, la fonction inertielle de manière contrôlée, ce qui est particulièrement favorable à une augmentation du confort de roulage du véhicule sur route normale tout en assurant un amortissement suffisant lors de débattements plus importants, comme par exemple sur des routes en mauvais état. Aussi, la réalisation d'une chambre auxiliaire pour la désactivation de la fonction inertielle procure davantage de flexibilité d'ajustement.The measures of the invention are interesting in that they make it possible to produce a particularly efficient shock absorber while remaining simple and compact in construction. In fact, the fact of providing the shock absorber and inertial hydraulic circuits concentrically makes it possible to limit the length of the shock absorber. The fact of providing, for the second sliding element, in addition to the rod and the piston cooperating with the cylinder of the first sliding element, an external cylinder surrounding the first sliding element makes it possible to produce in a particularly compact and fairly simple manner a second chamber, in external occurrence, and thus a second hydraulic circuit. Also, the concentric arrangement makes it possible to obtain a large thrust surface of the circumferential piston, which makes it possible to reduce the inertial mass of the hydraulic fluid. Furthermore, the fact of forming the volume of inertial hydraulic fluid by a groove in the wall along which a piston slides, is advantageous in that the inertial passage for the fluid is directly in the hydraulic chamber and is thus protected from attacks. external, such as corrosion. Also, this construction avoids the difficulties of achieving sealing with a conduit as in the state of the art. Also, thanks to this construction, the pitch of the helical groove can be varied in order to vary the mass of inertial hydraulic fluid as a function of the sliding level of the first element relative to the second. The closing and relief valves make it possible to activate and deactivate, respectively, the inertial function in a controlled manner, which is particularly favorable to increasing the driving comfort of the vehicle on normal roads while ensuring sufficient damping during longer travel. important, such as on roads in poor condition. Also, the creation of an auxiliary chamber for deactivation of the inertial function provides more flexibility of adjustment.

D'autres caractéristiques et avantages de la présente invention seront mieux compris à l'aide de la description et des dessins parmi lesquels :

  • La figure 1 est une vue en coupe schématique d'un amortisseur selon un premier mode de réalisation de l'invention ;
  • La figure 2 est une vue suivant la coupe II-II à la figure 1 ;
  • La figure 3 est une vue en coupe schématique d'une variante de l'amortisseur de la figure 1 ;
  • La figure 4 est une vue en coupe schématique d'un amortisseur selon un deuxième mode de réalisation de l'invention ;
  • La figure 5 est une vue suivant la coupe V-V à la figure 4.
Other characteristics and advantages of the present invention will be better understood with the help of the description and the drawings including:
  • There figure 1 is a schematic sectional view of a shock absorber according to a first embodiment of the invention;
  • There figure 2 is a view following section II-II at figure 1 ;
  • There Figure 3 is a schematic sectional view of a variant of the shock absorber of the figure 1 ;
  • There Figure 4 is a schematic sectional view of a shock absorber according to a second embodiment of the invention;
  • There figure 5 is a view following section VV at the Figure 4 .

Les figures 1 à 3 illustrent un premier mode de réalisation de l'invention.THE figures 1 to 3 illustrate a first embodiment of the invention.

La figure 1 est une vue schématique, en coupe longitudinale, d'un amortisseur de chocs conforme à un premier mode de réalisation de l'invention. La coupe longitudinale passe par l'axe de l'amortisseur 2. Ce dernier comprend, essentiellement, un premier élément 4 et un deuxième élément 6, aptes à coulisser l'un par rapport à l'autre. Chacun des premier et deuxième éléments coulissants 4 et 6 est destiné à être fixé, au choix, à une pièce mobile de la suspension d'un véhicule ou à une pièce fixe de la carrosserie dudit véhicule, respectivement. Plus particulièrement, le premier élément 4 comprend un cylindre 8 délimitant une première chambre généralement cylindrique 10. Il comprend également une portion annulaire extérieure 12 formant un piston annulaire. Le deuxième élément 6 comprend, quant à lui, un piston 14 supporté par une tige 16 et monté coulissant dans la chambre cylindrique 10. A cet effet, le cylindre 8 est fermé à chacune de ses deux extrémités, la fermeture traversée par la tige (en haut suivant l'orientation de la figure 1) comportant des moyens d'étanchéité (non représentés) avec la tige 16, ces moyens étant en soi bien connus de l'homme de métier. La chambre 10 comprend un fluide hydraulique, avantageusement visqueux avec une viscosité supérieure ou égale à celle du liquide de suspension Citroën® (LDS), à savoir supérieure ou égale à 18 mm2/s à 40°C et/ou 5.9 mm2/s à 100°C. Le piston 14 comprend un ou plusieurs passages à restriction potentiellement variable en fonction de différence de pression (non représentés), reliant les deux portions de chambre 10, de manière à ce qu'un coulissement relatif entre, d'une part, le piston 14 et la tige 16, et d'autre part le cylindre 8 provoque une circulation forcée du fluide hydraulique au travers du ou des passages à restriction sur le piston 14. La résistance à l'écoulement au travers de ce ou ces passages génère au niveau de la tige 16 et au niveau du cylindre 8 des efforts qui sont essentiellement proportionnels à la vitesse d'écoulement du fluide et donc de la vitesse de coulissement relatif entre le piston 14 et le cylindre. Ce principe d'amortissement est bien connu en soi de l'homme de métier.There figure 1 is a schematic view, in longitudinal section, of a shock absorber according to a first embodiment of the invention. The longitudinal section passes through the axis of the shock absorber 2. The latter essentially comprises a first element 4 and a second element 6, capable of sliding relative to each other. Each of the first and second sliding elements 4 and 6 is intended to be fixed, as desired, to a moving part of the suspension of a vehicle or to a fixed part of the bodywork of said vehicle, respectively. More particularly, the first element 4 comprises a cylinder 8 delimiting a first generally cylindrical chamber 10. It also comprises an outer annular portion 12 forming an annular piston. The second element 6 comprises, for its part, a piston 14 supported by a rod 16 and slidably mounted in the cylindrical chamber 10. For this purpose, the cylinder 8 is closed at each of its two ends, the closure crossed by the rod ( at the top following the orientation of the figure 1 ) comprising sealing means (not shown) with the rod 16, these means being in themselves well known to those skilled in the art. The chamber 10 comprises a hydraulic fluid, advantageously viscous with a viscosity greater than or equal to that of Citroën ® suspension fluid (LDS), namely greater than or equal to 18 mm 2 /s at 40°C and/or 5.9 mm 2 / s at 100°C. The piston 14 comprises one or more passages with potentially variable restriction as a function of pressure difference (not shown), connecting the two chamber portions 10, so that relative sliding enters, on the one hand, the piston 14 and the rod 16, and on the other hand the cylinder 8 causes a forced circulation of the hydraulic fluid through the restricted passage(s) on the piston 14. The resistance to the flow through this or these passages generates at the level of the rod 16 and at the level of the cylinder 8 forces which are essentially proportional to the speed of flow of the fluid and therefore to the speed of relative sliding between the piston 14 and the cylinder. This principle of depreciation is well known in itself to those skilled in the art.

Le deuxième élément coulissant 6 de l'amortisseur 2 comprend, outre le piston 14 et la tige 16, un cylindre extérieur 18 entourant le cylindre 8 du premier élément coulissant 4, et, partant, la tige 16 et le piston 14. Le cylindre extérieur 18 est rigidement lié à la tige 16. Plus spécifiquement, le cylindre extérieur 18 est monté coulissant sur la surface cylindrique extérieure du cylindre 8. Il comprend une paroi 20 entourant le cylindre 8 et à distance radialement dudit cylindre afin de former, avec ladite surface cylindrique extérieure, une deuxième chambre 22 annulaire. Celle-ci comprend un piston annulaire 12 lié au cylindre 8. Ce piston sépare par ailleurs la deuxième chambre 22 en deux portions de chambre 22.1 et 22.2. La paroi 20 délimitant la chambre 22 présente sur sa surface intérieure 20.1 une rainure 24 formée de manière hélicoïdale, notamment par usinage dans l'épaisseur de la paroi 20 depuis la surface intérieure 20.1. Le piston annulaire 12 s'étend axialement sur au moins un tour de la rainure hélicoïdale, préférentiellement sur au moins deux tours de ladite rainure, plus préférentiellement encore sur au moins trois tours ou plus. Le piston annulaire 12 comprend au moins un passage axial de fuite 26 et au moins un clapet de fermeture 28 maintenu en position axialement neutre par les ressorts 30. Dans cette position neutre, le clapet de fermeture 28 bien qu'obturant au moins en majeure partie le passage 26, peut se déplacer axialement entre les butées et sièges 32. La deuxième chambre 22 est remplie d'un fluide hydraulique, préférentiellement différent de celui de la première chambre. Ce fluide est avantageusement un fluide lourd de faible viscosité, en l'occurrence de viscosité inférieure ou égale à celle du glycol. Lors d'un mouvement de coulissement relatif entre les premier et deuxième éléments coulissants 4 et 6 de l'amortisseur, outre les phénomènes de passage du fluide de la première chambre 10 au travers du piston 14, mentionnés ci-avant, les volumes de portions 22.1 et 22.2 de la chambre 22 vont varier dans des sens opposés et, partant, provoquer un passage du fluide au travers et le long de la portion de la rainure 24 qui est située en vis-à-vis du piston annulaire 12. Le volume de cette portion de la rainure 24 étant rempli du fluide hydraulique, la masse correspondante dudit fluide forme ainsi une masse qui est mise en mouvement par le coulissement relatif entre les premier et deuxième éléments 14 et 16, générant ainsi une force d'amortissement qui est proportionnelle à l'accélération du mouvement de coulissement relatif entre les premier et deuxième éléments coulissants 14 et 16.The second sliding element 6 of the shock absorber 2 comprises, in addition to the piston 14 and the rod 16, an outer cylinder 18 surrounding the cylinder 8 of the first sliding element 4, and, therefore, the rod 16 and the piston 14. The outer cylinder 18 is rigidly linked to the rod 16. More specifically, the outer cylinder 18 is slidably mounted on the outer cylindrical surface of the cylinder 8. It comprises a wall 20 surrounding the cylinder 8 and at a radial distance from said cylinder in order to form, with said surface external cylindrical, a second annular chamber 22. This comprises an annular piston 12 linked to the cylinder 8. This piston also separates the second chamber 22 into two chamber portions 22.1 and 22.2. The wall 20 delimiting the chamber 22 has on its interior surface 20.1 a groove 24 formed helically, in particular by machining in the thickness of the wall 20 from the interior surface 20.1. The annular piston 12 extends axially over at least one turn of the helical groove, preferably over at least two turns of said groove, more preferably still over at least three turns or more. The annular piston 12 comprises at least one axial leakage passage 26 and at least one closing valve 28 held in an axially neutral position by the springs 30. In this neutral position, the closing valve 28 although closing at least for the most part the passage 26 can move axially between the stops and seats 32. The second chamber 22 is filled with a hydraulic fluid, preferably different from that of the first chamber. This fluid is advantageously a heavy fluid of low viscosity, in this case with a viscosity less than or equal to that of glycol. During a relative sliding movement between the first and second sliding elements 4 and 6 of the shock absorber, in addition to the phenomena of passage of the fluid from the first chamber 10 through the piston 14, mentioned above, the volumes of portions 22.1 and 22.2 of the chamber 22 will vary in opposite directions and, therefore, cause the fluid to pass through and along the portion of the groove 24 which is located opposite the annular piston 12. The volume of this portion of the groove 24 being filled with the hydraulic fluid, the corresponding mass of said fluid thus forms a mass which is set in motion by the relative sliding between the first and second elements 14 and 16, thus generating a damping force which is proportional to the acceleration of the relative sliding movement between the first and second sliding elements 14 and 16.

Lors de mouvements de coulissement de faibles amplitudes, l'inertie de la masse du fluide dans la portion de la rainure 24 en vis-à-vis du piston annulaire 12 génère une légère pression dans la portion de chambre 22 qui subit une diminution de son volume. Cette pression va alors déplacer axialement le clapet de fermeture 28 contre l'effort du ressort 30 situé du côté de l'autre portion de la chambre 22, c'est-à-dire celle qui subit une augmentation de volume. Cela signifie que l'effet d'amortissement par effet d'inertie ne commence véritablement que lorsque le clapet de fermeture 28 arrive en butée sur son siège 32 et ainsi ferme le passage 26. Le fluide sera alors mis en mouvement par écoulement dans la rainure 24 en vis-à-vis du piston annulaire 12.During sliding movements of small amplitudes, the inertia of the mass of the fluid in the portion of the groove 24 opposite the annular piston 12 generates a slight pressure in the chamber portion 22 which undergoes a reduction in its volume. This pressure will then move axially the closing valve 28 against the force of the spring 30 located on the side of the other portion of the chamber 22, that is to say that which undergoes an increase in volume. This means that the damping effect by inertia effect only really begins when the closing valve 28 abuts on its seat 32 and thus closes the passage 26. The fluid will then be set in motion by flow in the groove 24 opposite the annular piston 12.

En d'autres termes, le passage 26 dans le piston annulaire 12, combiné au clapet de fermeture 28 maintenu en position centrale par les ressorts 30 et apte à se déplacer axialement sur une course donnée, permet au circuit hydraulique inertiel formé dans la deuxième chambre 22 de n'être actif que pour des débattements de suspension supérieurs à une limite donnée. La course peut être supérieure à 2mm et/ou inférieure à 40mm.In other words, the passage 26 in the annular piston 12, combined with the closing valve 28 held in the central position by the springs 30 and capable of moving axially over a given stroke, allows the inertial hydraulic circuit formed in the second chamber 22 to only be active for suspension travel greater than a given limit. The stroke can be greater than 2mm and/or less than 40mm.

La figure 2 est une vue en coupe II-II de l'amortisseur de la figure 1, au niveau du piston annulaire 12. On peut observer que le clapet de fermeture 28 décrit ci-avant s'étend de manière circonférentielle, en l'occurrence sur un demi-tour. Il est cependant entendu que d'autres configurations, comme notamment ¾ de tour, voire plus, sont également envisageables. On peut observer que le piston annulaire 12 peut également comprendre un ou plusieurs clapets de décharge 34, disposés d'un point de vue fluidique en parallèle au clapet de fermeture 28. Ces clapets de décharge 34 sont configurés pour s'ouvrir et donc laisser passer le fluide en présence d'une différence de pression atteignant ou dépassant une limite prédéterminée. Cela permet au circuit hydraulique inertiel de limiter son effet en présence de mouvements de coulissement avec une grande accélération.There figure 2 is a sectional view II-II of the shock absorber of the figure 1 , at the level of the annular piston 12. It can be observed that the closing valve 28 described above extends circumferentially, in this case over a half-turn. However, it is understood that other configurations, such as ¾ turn, or even more, are also possible. It can be observed that the annular piston 12 can also comprise one or more discharge valves 34, arranged from a fluidic point of view in parallel to the closing valve 28. These discharge valves 34 are configured to open and therefore allow passage the fluid in the presence of a pressure difference reaching or exceeding a predetermined limit. This allows the inertial hydraulic circuit to limit its effect in the presence of sliding movements with great acceleration.

Il est à noter qu'il est préférable que la désactivation du circuit inertiel puisse se faire dans les deux sens, c'est-à-dire lorsque l'amortisseur est en compression ou attaque, et lorsqu'il est en extension ou détente. A cet effet, au moins un clapet de décharge peut alors être prévu dans chacune des directions d'écoulement entre les deux portions 22.1 et 22.2 de la chambre 22.It should be noted that it is preferable that the deactivation of the inertial circuit can be done in both directions, that is to say when the shock absorber is in compression or attack, and when it is in extension or relaxation. For this purpose, at least one relief valve can then be provided in each of the flow directions between the two portions 22.1 and 22.2 of the chamber 22.

Il est à noter que le ou les clapets de décharge 34 peuvent être disposés sur le clapet de fermeture 28. Ce dernier peut être formé de plusieurs éléments répartis sur la circonférence du piston 12.It should be noted that the discharge valve(s) 34 can be arranged on the closing valve 28. The latter can be formed of several elements distributed over the circumference of the piston 12.

Il est aussi à noter que le pas d'enroulement de la rainure hélicoïdale peut être variable de manière à varier la masse inertielle en fonction du degré d'enfoncement de l'amortisseur.It should also be noted that the winding pitch of the helical groove can be variable so as to vary the inertial mass depending on the degree of depression of the shock absorber.

La figure 3 illustre une variante de l'amortisseur de la figure 1, où deux pistons annulaires 12.1 et 12.2 sont disposés dans la chambre 22, à distance axiale l'un de l'autre. Chacun comprend un passage 26.1 et 26.2 pour le fluide hydraulique, et aussi un clapet de fermeture 28.1 et 28.2 maintenu par des ressorts 30.1 et 30.2, respectivement. On peut observer que pour le premier piston 12.1, la course du clapet de fermeture 28.1 est inférieure à celle du clapet de fermeture 28.2 du deuxième piston 12.2. On peut également observer que le nombre de tours que fait la rainure 24 en vis-à-vis du premier piston 12.1 et différent, en l'occurrence inférieur, au nombre de tours que fait la rainure 24 en vis-à-vis du deuxième piston 12.2. Une telle configuration est intéressante en ce qu'elle permet d'utiliser deux masses d'inertie différentes avantageusement avec des seuils d'activation différents. Aussi des clapets de décharge de caractéristiques différentes peuvent être prévus sur ces pistons 12.1 et 12.2, ce qui permet d'obtenir des seuils de saturation différents.There Figure 3 illustrates a variant of the shock absorber of the figure 1 , where two annular pistons 12.1 and 12.2 are arranged in the chamber 22, at an axial distance from one another. Each includes a passage 26.1 and 26.2 for the hydraulic fluid, and also a closing valve 28.1 and 28.2 held by springs 30.1 and 30.2, respectively. It can be observed that for the first piston 12.1, the stroke of the closing valve 28.1 is less than that of the closing valve 28.2 of the second piston 12.2. It can also be observed that the number of turns made by the groove 24 opposite the first piston 12.1 is different, in this case lower, than the number of turns made by the groove 24 opposite the second piston 12.2. Such a configuration is interesting in that it allows the use of two different inertia masses advantageously with different activation thresholds. Also discharge valves of different characteristics can be provided on these pistons 12.1 and 12.2, which makes it possible to obtain different saturation thresholds.

L'amortisseur qui vient d'être décrit est particulièrement intéressant en ce qu'il combine un circuit hydraulique à amortissement classique et à un circuit hydraulique inertiel, et ce de manière compacte, économique et performante. Le circuit hydraulique inertiel permet en effet de participer à l'amortissement pour les plus grands débattements, ce qui permet de prévoir un niveau d'amortissement classique plus faible, procurant ainsi un plus grand confort sur route normale.The shock absorber which has just been described is particularly interesting in that it combines a hydraulic circuit with conventional damping and an inertial hydraulic circuit, and this in a compact, economical and efficient manner. The inertial hydraulic circuit makes it possible to participate in damping for greater travel, which makes it possible to provide a lower level of classic damping, thus providing greater comfort on normal roads.

Les figures 4 et 5 sont des vues schématiques, en coupe longitudinale, d'un amortisseur 102 selon un second mode de réalisation de l'invention.THE figures 4 and 5 are schematic views, in longitudinal section, of a shock absorber 102 according to a second embodiment of the invention.

Comme pour le premier mode de réalisation, tout au long de la description est entendu par le terme de paroi axiale une paroi orientée selon un axe vertical de l'amortisseur 102 suivant l'orientation de la figure 4 et par le terme de paroi radiale une paroi orientée selon un axe horizontal de l'amortisseur 102 toujours suivant l'orientation de la figure 4.As for the first embodiment, throughout the description the term axial wall is understood to mean a wall oriented along a vertical axis of the shock absorber 102 following the orientation of the Figure 4 and by the term radial wall a wall oriented along a horizontal axis of the shock absorber 102 always following the orientation of the Figure 4 .

La coupe longitudinale passe par l'axe de symétrie de l'amortisseur 102.The longitudinal section passes through the axis of symmetry of the shock absorber 102.

L'amortisseur 102 comporte un premier élément 104 et un deuxième élément 106, aptes à coulisser l'un par rapport à l'autre.The shock absorber 102 comprises a first element 104 and a second element 106, capable of sliding relative to each other.

Chacun des premier et deuxième éléments 104 et 106 est destiné à être fixé, au choix, à une pièce mobile de la suspension d'un véhicule ou à une pièce fixe de la carrosserie dudit véhicule, respectivement.Each of the first and second elements 104 and 106 is intended to be fixed, as desired, to a moving part of the suspension of a vehicle or to a fixed part of the bodywork of said vehicle, respectively.

Plus particulièrement, le premier élément 104 comprend un cylindre intérieur 108 délimitant une chambre intérieure 110 généralement cylindrique.More particularly, the first element 104 comprises an interior cylinder 108 delimiting a generally cylindrical interior chamber 110.

Le deuxième élément 106 comprend un piston intérieur 114 supporté par une tige 116 et monté coulissant dans la chambre intérieure 110.The second element 106 comprises an interior piston 114 supported by a rod 116 and slidably mounted in the interior chamber 110.

A cet effet, le cylindre intérieur 108 est fermé à chacune de ses deux extrémités axiales, la fermeture supérieure étant traversée par la tige 116 (suivant l'orientation de la figure 4) et comporte des moyens d'étanchéité (non représentés) avec la tige 116, ces moyens d'étanchéité étant en soi bien connus de l'homme de métier.For this purpose, the interior cylinder 108 is closed at each of its two axial ends, the upper closure being crossed by the rod 116 (following the orientation of the Figure 4 ) and comprises sealing means (not shown) with the rod 116, these sealing means being in themselves well known to those skilled in the art.

La chambre intérieure 110 comprend un fluide hydraulique, avantageusement visqueux avec une viscosité supérieure ou égale à celle du liquide de suspension Citroën® (LDS), à savoir supérieure ou égale à 18 mm2/s à 40°C et/ou 5.9 mm2/s à 100°C.The inner chamber 110 comprises a hydraulic fluid, advantageously viscous with a viscosity greater than or equal to that of Citroën ® suspension fluid (LDS), namely greater than or equal to 18 mm 2 /s at 40°C and/or 5.9 mm 2 /s at 100°C.

Le piston intérieur 114 comprend un ou plusieurs passages à restriction potentiellement variable en fonction de différence de pression (non représentés), reliant les deux portions de la chambre intérieure 110, de manière à ce qu'un coulissement relatif entre, d'une part, le piston intérieur 114 et la tige 116, et d'autre part le cylindre intérieur 108 provoque une circulation forcée du fluide hydraulique au travers du ou des passages à restriction sur le piston intérieur 114.The interior piston 114 comprises one or more passages with potentially variable restriction as a function of pressure difference (not shown), connecting the two portions of the interior chamber 110, so that relative sliding enters, on the one hand, the inner piston 114 and the rod 116, and on the other hand the inner cylinder 108 causes a forced circulation of the hydraulic fluid through the restricted passage(s) on the inner piston 114.

La résistance à l'écoulement au travers de ce ou ces passages génère au niveau de la tige 116 et au niveau du cylindre intérieur 108, des efforts qui sont essentiellement proportionnels à la vitesse d'écoulement du fluide et donc de la vitesse de coulissement relatif entre le piston intérieur 114 et le cylindre intérieur 108, ce principe d'amortissement étant bien connu en soi de l'homme de métier.The resistance to flow through this or these passages generates, at the level of the rod 116 and at the level of the internal cylinder 108, forces which are essentially proportional to the flow speed of the fluid and therefore to the speed of relative sliding between the inner piston 114 and the inner cylinder 108, this damping principle being well known in itself to those skilled in the art.

Le deuxième élément 106 de l'amortisseur 102 comprend, outre le piston intérieur 114 et la tige 116, un cylindre extérieur 118 entourant le cylindre intérieur 108 du premier élément 104, et, partant, la tige 116 et le piston intérieur 114.The second element 106 of the shock absorber 102 comprises, in addition to the inner piston 114 and the rod 116, an outer cylinder 118 surrounding the inner cylinder 108 of the first element 104, and, therefore, the rod 116 and the inner piston 114.

Le cylindre extérieur 118 est rigidement lié à la tige 116. Plus spécifiquement, le cylindre extérieur 118 est monté coulissant sur la surface cylindrique extérieure du cylindre intérieur 108.The outer cylinder 118 is rigidly linked to the rod 116. More specifically, the outer cylinder 118 is slidably mounted on the outer cylindrical surface of the inner cylinder 108.

Le cylindre extérieur 118 comporte une cavité qui est formée le long de sa surface cylindrique intérieure.The outer cylinder 118 has a cavity that is formed along its inner cylindrical surface.

Le cylindre extérieur 118 est positionné de manière coulissante et étanche, aux deux extrémités de ladite cavité, autour du cylindre intérieur 108.The outer cylinder 118 is positioned in a sliding and sealed manner, at both ends of said cavity, around the inner cylinder 108.

Dans ladite cavité du cylindre extérieur 118 est positionné un élément intermédiaire 120 de forme cylindrique.In said cavity of the outer cylinder 118 is positioned an intermediate element 120 of cylindrical shape.

Entre la surface cylindrique intérieure de la cavité du cylindre extérieur 118 et la surface cylindrique extérieure de l'élément intermédiaire 120 et la surface cylindrique extérieure du cylindre intérieur 108, est délimitée une chambre extérieure 125.Between the interior cylindrical surface of the cavity of the exterior cylinder 118 and the exterior cylindrical surface of the intermediate element 120 and the exterior cylindrical surface of the interior cylinder 108, an exterior chamber 125 is delimited.

L'élément intermédiaire 120 comporte une cavité qui est formée le long de sa surface cylindrique intérieure.The intermediate member 120 has a cavity which is formed along its inner cylindrical surface.

L'élément intermédiaire 120 est positionné de manière coulissante et étanche, à ces deux extrémités, autour du cylindre intérieur 108.The intermediate element 120 is positioned in a sliding and sealed manner, at these two ends, around the inner cylinder 108.

Entre la surface cylindrique intérieure de la cavité de l'élément intermédiaire 120 et la surface cylindrique extérieure du cylindre extérieur 118 est délimitée une chambre intermédiaire 122 dite chambre annulaire.Between the interior cylindrical surface of the cavity of the intermediate element 120 and the exterior cylindrical surface of the exterior cylinder 118 is delimited an intermediate chamber 122 called an annular chamber.

Le cylindre intérieur 108 comporte une collerette, en saillie de sa surface cylindrique extérieure, qui forme un piston intermédiaire 112, de forme annulaire, apte à coulisser le long de la chambre annulaire 122 en fonction du mouvement relatif entre le cylindre intérieur 108 et l'élément intermédiaire 120.The inner cylinder 108 comprises a collar, projecting from its outer cylindrical surface, which forms an intermediate piston 112, of annular shape, capable of sliding along the annular chamber 122 as a function of the relative movement between the inner cylinder 108 and the intermediate element 120.

Le piston intermédiaire 112 sépare la chambre annulaire 122 en deux portions 122.1 et 122.2. Suivant l'orientation de l'amortisseur 102 tel que représenté à la figure 4, est formée une portion supérieure 122.1 de la chambre annulaire 122 et une portion inférieure 122.2 de chambre annulaire 122.The intermediate piston 112 separates the annular chamber 122 into two portions 122.1 and 122.2. Depending on the orientation of the shock absorber 102 as shown in Figure 4 , is formed an upper portion 122.1 of the annular chamber 122 and a lower portion 122.2 of the annular chamber 122.

De part et d'autre du piston intermédiaire 112 est positionné un ressort 127 en appui entre chacun des deux bords axiaux de la chambre annulaire 122 et la face correspondante du piston annulaire 112, faisant que, toujours suivant l'orientation de l'amortisseur tel que représenté à la figure 104, un premier ressort haut 127.1 est positionné dans la portion supérieur 122.1 de la chambre annulaire 122 et un second ressort bas 127.2 est positionné dans la portion inférieure 122.2 de la chambre annulaire 122.On either side of the intermediate piston 112 is positioned a spring 127 bearing between each of the two axial edges of the annular chamber 122 and the corresponding face of the annular piston 112, so that, always following the orientation of the shock absorber as as shown in Figure 104, a first top spring 127.1 is positioned in the upper portion 122.1 of the annular chamber 122 and a second bottom spring 127.2 is positioned in the lower portion 122.2 of the annular chamber 122.

L'élément intermédiaire 120 présente le long de sa surface intérieure radiale une rainure 124 formée de manière hélicoïdale, notamment par usinage dans l'épaisseur de la paroi intermédiaire 120 depuis sa surface intérieure radiale.The intermediate element 120 has along its radial interior surface a groove 124 formed in a helical manner, in particular by machining in the thickness of the intermediate wall 120 from its radial interior surface.

Le piston annulaire 112 s'étend axialement sur au moins un tour de la rainure hélicoïdale 124, préférentiellement sur au moins deux tours de ladite rainure hélicoïdale 124, plus préférentiellement encore sur au moins trois tours ou plus.The annular piston 112 extends axially over at least one turn of the helical groove 124, preferably over at least two turns of said helical groove 124, more preferably still over at least three turns or more.

Il est aussi à noter que le pas d'enroulement de la rainure hélicoïdale peut être variable le long de la surface intérieure radiale de l'élément intermédiaire 120, de manière à varier la masse inertielle en fonction du degré d'enfoncement de l'amortisseur 112.It should also be noted that the winding pitch of the helical groove can be variable along the radial interior surface of the intermediate element 120, so as to vary the inertial mass as a function of the degree of depression of the shock absorber. 112.

Le piston intermédiaire 112 comprend au moins un passage axial de fuite 126 et au moins un clapet de fermeture 128 maintenu en position axialement neutre par des ressorts 130 positionnés de part et d'autre dudit clapet de fermeture 128.The intermediate piston 112 comprises at least one axial leakage passage 126 and at least one closing valve 128 held in an axially neutral position by springs 130 positioned on either side of said closing valve 128.

Des butées 132 positionnées aux deux extrémités du passage axial de fuite 126, forment des surfaces d'appui pour les ressorts 130 du piston intermédiaire 112.Stops 132 positioned at both ends of the axial leakage passage 126 form bearing surfaces for the springs 130 of the intermediate piston 112.

Dans la position neutre telle que représentée, le clapet de fermeture 128, bien qu'obturant au moins en majeure partie le passage 126, peut se déplacer axialement entre les butées 132.In the neutral position as shown, the closing valve 128, although blocking at least the majority of the passage 126, can move axially between the stops 132.

La chambre annulaire 122 est remplie d'un fluide hydraulique, préférentiellement différent de celui de la chambre intérieure 110.The annular chamber 122 is filled with a hydraulic fluid, preferably different from that of the interior chamber 110.

Ce fluide est avantageusement un fluide lourd de faible viscosité, en l'occurrence de viscosité inférieure ou égale à celle du glycol.This fluid is advantageously a heavy fluid of low viscosity, in this case with a viscosity less than or equal to that of glycol.

Une bague 123 délimite en deux portions 125.1 et 125.2 la chambre extérieure 125.A ring 123 delimits the outer chamber 125 into two portions 125.1 and 125.2.

La chambre extérieure 125 est séparée de la chambre annulaire 122 et de la chambre intérieure 110, permettant d'y prévoir un fluide hydraulique potentiellement différent de celui notamment de la chambre annulaire 122.The outer chamber 125 is separated from the annular chamber 122 and the inner chamber 110, making it possible to provide a hydraulic fluid potentially different from that in particular of the annular chamber 122.

Différents clapets sont prévus le long de la bague 123, notamment un premier clapet de décharge 133 qui permet un échange de fluide de la première portion 125.1 de la chambre extérieure 125 vers la seconde portion 125.2 de la chambre extérieure 125.Different valves are provided along the ring 123, in particular a first discharge valve 133 which allows an exchange of fluid from the first portion 125.1 of the outer chamber 125 towards the second portion 125.2 of the outer chamber 125.

Un second clapet de décharge 134 qui permet un échange de fluide de la seconde portion 125.2 de la chambre extérieure 125 vers la première portion 125.1 de la chambre extérieure 125.A second discharge valve 134 which allows an exchange of fluid from the second portion 125.2 of the outer chamber 125 towards the first portion 125.1 of the outer chamber 125.

Un clapet de fuite 135 permettant une fuite permanente calibrée du fluide hydraulique entre les deux portions 125.1 et 125.2 de la chambre extérieure 125.A leak valve 135 allowing a permanent calibrated leak of the hydraulic fluid between the two portions 125.1 and 125.2 of the outer chamber 125.

Lors d'un mouvement de coulissement relatif entre les premier et deuxième éléments 104 et 106 de l'amortisseur 102, outre les phénomènes de passage du fluide de la chambre intérieure 110 au travers du piston 114, mentionnés ci-avant, les volumes de portions 122.1 et 122.2 de la chambre 122 vont varier dans des sens opposés et, partant, provoquer un passage du fluide au travers et le long de la portion de la rainure 124 qui est située en vis-à-vis du piston annulaire 112.During a relative sliding movement between the first and second elements 104 and 106 of the shock absorber 102, in addition to the phenomena of passage of the fluid from the interior chamber 110 through the piston 114, mentioned above, the volumes of portions 122.1 and 122.2 of the chamber 122 will vary in opposite directions and, therefore, cause the fluid to pass through and along the portion of the groove 124 which is located opposite the annular piston 112.

Le volume de cette portion de la rainure 124 étant rempli du fluide hydraulique, la masse correspondante dudit fluide forme ainsi une masse qui est mise en mouvement par le coulissement relatif entre les premier et deuxième 104 et 106, générant ainsi une force d'amortissement qui est proportionnelle à l'accélération du mouvement de coulissement relatif entre les premier et deuxième éléments 104 et 106.The volume of this portion of the groove 124 being filled with the hydraulic fluid, the corresponding mass of said fluid thus forms a mass which is set in motion by the relative sliding between the first and second 104 and 106, thus generating a damping force which is proportional to the acceleration of the relative sliding movement between the first and second elements 104 and 106.

Plus spécifiquement, la paroi intermédiaire 120 est maintenue axialement en position centrale par les ressorts 127.More specifically, the intermediate wall 120 is held axially in the central position by the springs 127.

Le piston intermédiaire 112 avantageusement ne comporte pas de clapets de décharge, ceux-ci étant prévus sur la bague 123 qui délimite en deux portions 125.1 et 125.2 la chambre extérieure 125.The intermediate piston 112 advantageously does not include relief valves, these being provided on the ring 123 which delimits the outer chamber 125 into two portions 125.1 and 125.2.

Le fonctionnement de l'amortisseur est donc le suivant.The operation of the shock absorber is therefore as follows.

En cas de sollicitations avec des faibles débattements, le clapet de fermeture 128 manque de buter sur les sièges 132, ce qui a pour effet que le circuit hydraulique inertiel ne génère pas de force significative et est par conséquent inactif.In the event of stress with low travel, the closing valve 128 fails to abut on the seats 132, which has the effect that the inertial hydraulic circuit does not generate significant force and is therefore inactive.

En cas de débattements plus importants, en l'occurrence des débattements qui ont pour effet d'amener le clapet de fermeture 128 contre au moins une des butées 132, le fluide hydraulique de la chambre 122 est déplacé le long de la portion de rainure 124 en vis-à-vis du piston 112, générant ainsi un effort résistant du type inertiel.In the event of greater movements, in this case movements which have the effect of bringing the closing valve 128 against at least one of the stops 132, the hydraulic fluid from the chamber 122 is displaced along the groove portion 124 opposite the piston 112, thus generating a resistant force of the inertial type.

Cet effort résistant qui a tendance à déplacer la paroi 120 est repris par une augmentation de pression dans la portion de la chambre extérieure 125 dont le volume tend à diminuer par le déplacement de la paroi 120. Cette pression est transmise au clapets de décharge 133 et 134 et au clapet de fuite 135 sur la bague 123.This resistant force which tends to move the wall 120 is taken up by an increase in pressure in the portion of the outer chamber 125 whose volume tends to decrease by the movement of the wall 120. This pressure is transmitted to the discharge valves 133 and 134 and the leak valve 135 on the ring 123.

Lorsque le débattement génère une pression supérieure ou égale à la pression limite d'ouverture du ou des clapets de décharge, celui-ci/ceux-ci s'ouvrent et autorisent un passage du fluide depuis la portion de la chambre extérieure 125 qui en pression vers l'autre portion de ladite chambre extérieure 125, ce qui a pour effet de limiter la force résistante générée par le circuit hydraulique inertiel.When the travel generates a pressure greater than or equal to the limit opening pressure of the relief valve(s), the latter/these open and allow the passage of the fluid from the portion of the outer chamber 125 which is under pressure. towards the other portion of said outer chamber 125, which has the effect of limiting the resistant force generated by the inertial hydraulic circuit.

Un autre fluide que le fluide inertiel peut être utilisé pour coopérer avec les clapets de décharge 133 et 134.A fluid other than the inertial fluid can be used to cooperate with the discharge valves 133 and 134.

Cela procure davantage de finesse d'ajustement du comportement du circuit inertiel, en particulier au niveau de son seuil de désactivation.This provides more fine adjustment of the behavior of the inertial circuit, in particular at the level of its deactivation threshold.

Le circuit d'activation n'étant pas relié au circuit inertiel, les régimes de fonctionnement sont indépendants et mieux contrôlables.As the activation circuit is not connected to the inertial circuit, the operating speeds are independent and better controllable.

Il est à noter qu'il est préférable que la désactivation du circuit inertiel puisse se faire dans les deux sens, c'est-à-dire lorsque l'amortisseur est en compression ou attaque, et lorsqu'il est en extension ou détente.It should be noted that it is preferable that the deactivation of the inertial circuit can be done in both directions, that is to say when the shock absorber is in compression or attack, and when it is in extension or relaxation.

Alternativement, aux deux clapets de décharge, un seul clapet de décharge apte à travailler dans les deux sens peut être prévu.Alternatively, at the two relief valves, a single relief valve capable of working in both directions can be provided.

Le clapet de fuite calibré n'intervient que faiblement lors du fonctionnement de l'amortisseur et lors du fonctionnement du circuit inertiel, mais permet à l'ensemble de se repositionner dans la position neutre après avoir été sollicité pour une prochaine utilisation sachant que les deux clapets de décharges sont alors en position fermée.The calibrated leakage valve intervenes only slightly during the operation of the shock absorber and during the operation of the inertial circuit, but allows the assembly to reposition itself in the neutral position after having been requested for a next use knowing that both discharge valves are then in the closed position.

Claims (12)

  1. Shock absorber (2; 102) for motor vehicle suspension, comprising:
    - a first element (4; 104) intended to be fixed to one of a movable part of the suspension and a fixed part of the vehicle; And
    - a second element (6; 106) positioned concentrically around the first element (4; 104), capable of sliding axially relative to the first element (4; 104), and intended to be fixed to the other of the movable part of the suspension and the fixed part of the vehicle;
    the first and second elements (4, 6; 104, 106) forming a damping hydraulic circuit and an inertial hydraulic circuit,
    characterized in that the first element (4; 104) is a cylinder (8; 108) forming a cylindrical chamber (10; 110) and the second element (6; 106) comprises an internal piston (14; 114) slidably mounted in the cylindrical chamber (10; 110) and a rod (16; 116) linked to said inner piston (14, 114), said cylindrical chamber (10, 110) and said inner piston (14, 114) corresponding to one of the damper hydraulic circuits (10, 14; 110, 114) and inertial (12, 22; 112, 122, 125), and an external cylinder (18; 118) linked to the rod (16; 116) and concentrically surrounding the first element (4; 104) so as to slide along the outer wall of said first element (4; 104) and to form with the first element (4; 104) an outer chamber (22; 125), and where the first element (4; 104) ) comprises an outer annular portion forming at least one annular piston (12; 112), the shock absorber comprising a cylindrical wall (20; 120) concentrically surrounding a part of the first element (4; 104) to form an annular chamber (22; 122), the at least one piston (12; 112) sliding along said cylindrical wall (20; 120) in the annular chamber (22; 122), characterized in that the cylindrical wall (20; 120) comprises a helical groove (24; 124) forming, opposite the at least one piston (12; 122), at least one passage for the hydraulic fluid during sliding of the minus one piston (12; 112) along the cylindrical wall (20; 120).
  2. Shock absorber (2; 102) according to claim 3, characterized in that the helical groove (24; 124) has a variable pitch so as to vary the length of the passage(s) for the hydraulic fluid as a function of the sliding position of the at least one piston (12; 112) relative to the wall (20; 120).
  3. Shock absorber (2; 102) according to one of claims 2 and 3, characterized in that the at least one piston (12; 112) extends axially over at least two turns of the helical groove (24; 124).
  4. Shock absorber (2; 102) according to one of claims 2 to 5, characterized in that the at least one piston (12; 112) comprises at least one axial leakage passage (26; 126) for the hydraulic fluid and at least one at least one closing valve (28; 128) configured to close said passage when the sliding stroke of said at least one piston relative to the wall (20; 120) is greater than a predetermined value.
  5. Shock absorber (2) according to claim 6, characterized in that the outer chamber (22) also forms said annular chamber in which the at least one piston (12) is able to slide.
  6. Shock absorber (2) according to claim 7, characterized in that the at least one piston (12) comprises at least two pistons (12.1, 12.2), the closing valves (28.1, 28.2) of said pistons having different closing strokes .
  7. Shock absorber (2) according to claim 8, characterized in that the at least one piston (12) comprises at least one relief valve (34) capable of opening an axial discharge passage for the hydraulic fluid in the event of overpressure of said fluid.
  8. Shock absorber (102) according to any one of claims 1 to 6, characterized in that, between the first element (104) and the second element (106), is positioned a cylindrical intermediate wall (120) capable of sliding along the outer wall of the first element (104), said intermediate wall (120) delimiting the annular chamber (122) which is delimited on one side by said cylindrical wall and on the other side by the outer wall of the first element (104), comprising a hydraulic fluid, the piston (112) is able to slide along said annular chamber (122), said annular chamber (122) comprising return means (127) positioned between the piston (112) and the intermediate wall ( 120).
  9. Shock absorber (102) according to claim 10, characterized in that the return means (127) comprise at least two springs (127.1, 127.2), a first spring (27.1) being positioned in support between a first axial face of the piston (112). ) and a first edge facing the annular chamber (122) and a second spring (127.1) being positioned in support between a second axial face of the annular piston (112) and a second edge facing the annular chamber (122).
  10. Shock absorber (102) according to claim 10 or 11, characterized in that the outer chamber (125) comprises a hydraulic fluid and a ring (123) which delimits said outer chamber (125) into two portions (125.1, 125.2), said ring (123) being adapted to control the transfer of hydraulic fluid between the two portions (125.1, 125.2).
  11. Shock absorber (102) according to claim 12, characterized in that the ring (123) comprises at least one relief valve (133, 134) allowing an exchange of hydraulic fluid between the two portions (125.1, 125.2) of the outer chamber ( 125) beyond a certain fluid pressure in one of said two portions (125.1, 125.2) and a leak valve (135) allowing a calibrated permanent leak of the hydraulic fluid between the two portions (125.1, 125.2) of the chamber exterior (125).
  12. Vehicle comprising a suspension equipped with a shock absorber (2; 102) according to any one of the preceding claims.
EP19720967.9A 2018-04-17 2019-04-03 Fluid damper with inertial fluid damping for a vehicle suspension Active EP3781835B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR1853332A FR3080162B1 (en) 2018-04-17 2018-04-17 INERTIAL SHOCK ABSORBER FOR MOTOR VEHICLE SUSPENSION
FR1903247A FR3094435B1 (en) 2019-03-28 2019-03-28 INERTIAL DOUBLE CHAMBER SHOCK ABSORBER FOR AUTOMOTIVE VEHICLE SUSPENSION
PCT/FR2019/050779 WO2019202231A1 (en) 2018-04-17 2019-04-03 Hydraulic shock absorber with inertial fluid damping for the suspension of a motor vehicle

Publications (2)

Publication Number Publication Date
EP3781835A1 EP3781835A1 (en) 2021-02-24
EP3781835B1 true EP3781835B1 (en) 2024-02-21

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EP19720967.9A Active EP3781835B1 (en) 2018-04-17 2019-04-03 Fluid damper with inertial fluid damping for a vehicle suspension

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EP (1) EP3781835B1 (en)
WO (1) WO2019202231A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114737692B (en) * 2022-04-26 2023-06-20 湖北安尔固科技有限公司 Self-resetting buffer device

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2720944A (en) * 1950-01-13 1955-10-18 Girard Alexandre Auguste Leon Hydraulic vibration damper
US3237931A (en) * 1963-10-10 1966-03-01 Cousin Maurice Hydro-pneumatic or hydraulic jack devices
JPH02163531A (en) * 1988-12-16 1990-06-22 Haamo Sogo Kenkyusho:Kk Shock absorber
JP2000018308A (en) * 1998-06-25 2000-01-18 Tokico Ltd Hydraulic shock absorber
CN201427510Y (en) * 2009-07-03 2010-03-24 中国北车集团大同电力机车有限责任公司 Vibration absorber
WO2011089373A1 (en) * 2010-01-25 2011-07-28 Lotus Renault Gp Ltd Fluid inerter
JP5747045B2 (en) 2010-02-05 2015-07-08 ケンブリッジ・エンタープライズ・リミテッドＣａｍｂｒｉｄｇｅ Ｅｎｔｅｒｐｒｉｓｅ Ｌｉｍｉｔｅｄ Damping and inertia hydraulic system

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WO2019202231A1 (en) 2019-10-24

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